Underground Mine fires are the industries greatest hazard with disastrous toll on miner’s live and great losses of property and income for the mine. Most people think of coal mines fires, hardrock mines also burn, the most tragic were 1917 Granite Mountain mine in Butte Montana when 168 miners were killed and the 1972 Sunshine mine fire at Kellogg Idaho with loss of 91 miners. Despite the numerous fires underground in Bisbee only three men were killed though several were injured.
Types of underground mine fires
The most serious type of fire in Bisbee is when the sulfide minerals, pyrite and chalcopyrite are ignited either through spontaneous combustion or by another type of fire. The oxidation of pyrite and chalcopyrite is exothermic (heat generating) and is sufficient enough to cause spontaneous combustion of the minerals if the heat is allowed to build up. Friction from moving ground (cave in’s) is also known to have generated enough heat to ignite the rock. The burning properties of pyrite have been known for centuries, even the word pyrite comes from the Greek word pyros meaning fire. Pyrite has been used as an early fire starter and the ignition source on matchlock rifles. Pyrite and chalcopyrite burn so well because of their high sulfur content, pyrite is 53.3 percent sulfur, chalcopyrite is 34.9 percent. Pyritic ore dust ignites between 320C and 365C degrees and can burn in atmospheres with only 13 percent oxygen. In a recent mine accident (not in Bisbee), a front end loader hit the rib of a tunnel igniting the nearby pyrite dust. A high portion of coal mine fires are actually caused by pyrite inside the coal oxidizing and igniting. Sulfide fires will burn for years, glowing like embers, in 1994 the area around the Briggs fire was still hot.
Chemical reaction of burning pyrite
3 FeS2 + 802=Fe304 + 6S02↑
4 FeS2 + 1102=2Fe203 + 8S02↑
Electrical fires are usually caused by overloaded wires, worn insulation or faulty electrical devices. Hazards from this type of fire are fumes, electrocution and setting the timber on fire. None of Bisbee’s major mine fires were recorded caused by electricity, doubtless there were smaller fires caused by this.
Several timber fires occurred, Bisbee’s poor ground conditions required vast amounts of heavy timbering thought out the mines. The 1907 Shattuck fire started when the timber on the 800 level station caught fire. This fire was put out by spraying water down the shaft and sealing the connection to Cuprite shaft with a bulkhead. In the Late 1940’s and 1950’s the Copper Queen incline was intentionally set on fire. The Copper Queen incline was ignited by kids dropping a burning yucca down the shaft, which landed near the Queen tunnel level burning the shaft timber from that point to the surface. The Sunrise shaft timber was ignited by a wide-spread brush fire burning the shaft timber out completely. The Shattuck Shaft and all of the surface facilities were distroyed by this same brush fire, belived to have been accidently set by children.
These vandalism fire were especially dangerous because of how Bisbee’s mine interconnect, the gases could have easily gone from and abandoned section to and active section of another mine. An unusual fire was thought to have been caused by the dumping of molten slag from the smelter near a raise off the 100 drift in the Holbrook No1 mine igniting the timber.
Equipment fires were not as prominent in the past as they are today with diesel equipment being used, the fuel, oil and grease from these easily catch fire. In the past the fires were usually caused by overheated bearings. This type of fire was not the source of any major fire in Bisbee.
The fire that caused the horrific deaths of two men was odd in nature. The incident happen while sinking the Congdon shaft, three men were working at the bottom and were preparing to load a round with powder (dynamite). The powder ignited and burned fiercely, not exploding. The cause of this fire is unknown. The fire burned all three men severely burned, one man’s skull in split open from a fall which was the cause of death. The other two were recovered alive from the shaft, one later died from his burns.
Common causes of mine fires
Leaving candle snuffs burning
Careless use of matches
Spontaneous combustion of sulfides
Friction of moving ground (cave ins) igniting sulfides
Careless use of carbide lamps and candles
Sparks from welding and torches
Mine Fire procedures
To evacuate the mine, in the early years, they used to flash the electric lights nine times and then repeated, both underground and on the surface to warn the men of danger. Later a Stench system was added which replaced the flashing light or was used in conjunction with the stench. The stench was the chemical, Ethyl Mercaptan which gives off a strong rotten egg smell. The stench was released in the main compressed air line carrying the smell throughout the mine . Ethyl Mercaptan can be detected at ½ parts per billion this causes problems when training. After the stench was released in the compress airline it would take weeks to get rid of the smell so mines ended up just releasing the stench in the main ventilation during test hoping it would reach everywhere ,which is not very effective. Today mines are switching to a wintergreen stench that is less offensive and they can perform test in the correct manner. After the warning is received the miners will leave the mine by designated routes.
After the mine has been evacuated the next task is to determine where in the mine the fire is burning and then development a general plan of containing and putting it out. Helmet crews will then be sent in to find out the extent, seriousness of the fire and rescue any trapped miners. At this time the helmet crew will bulkhead of sections of the mine to control the ventilation to the fire country and keep the escaping gases from entering into the rest of the mine. In conjunction with the bulkheading , the mine ventilation system will be changed with fans to create positive air pressure ( 7lb per square ft) in the fire zone to keep gases from entering through cracks in the rock and around the bulkheads.
Putting the fire out will be difficult and is found to be sometimes, impossible. There are several basic methods used in Bisbee to fight fires.
Flooding the mine to above the fire zone, this was done for the Shattuck fire taking about three months for the water to rise above the fire. Problems with is that the flooding may require several years. If flooded with acid water which is typical of the water in Bisbee all the steel will be destroyed this will include pumps and pump lines used in the dewatering operations ( before stainless steel was available ). These problems can cause this technique to be cost prohibitive.
Drill holes from the surface to fire zone and pump water in. Difficulties with this were they have had trouble drilling holes above the fires because of the broken and caving ground. A benefit can be derived from this technique in sulfide fires, the water running through the fire zone will act as a leach solution dissolving the copper. Collecting the “copper water” below the fire zone, from which the copper can be recovered from the solution by making a precipitation plant underground.
Driving drifts above the fire and flooding them and letting the water seep into the fire zone. You can also drill hole from the drift and pump water into fire
Use fans to build up air pressure and force smoke and gases back towards point of the fire’s origin and mine the fire out
Bulkhead off fire zone letting it burn and keep surrounding area cool with ventilation to keep fire from spreading.
Shaft fires where sprinklers have been placed inside shaft. The sprinklers can only be turned on if the fire doors on all the shaft station are shut or all personal are out of the mine. The turning on the sprinklers will cause a change in ventilation pattern and can forces the fire gases into other parts of the mine
Shaft fires in wood timbered shafts without sprinklers should have steel shaft doors installed at the collar and these will be shut after all the miners have evacuated .
With fires, the main hazard will be the gases emitted both being poisonous (carbon monoxide) and acidic (sulfur dioxide). The ventilation will need to be controlled to direct the poisonous gases (mostly carbon dioxide) away from the active part of the mine with the use of fans and doors. The gases will have a high sulfur dioxide content this will combined with the moisture in the mine making sulfuric acid. The acid will attack the timber and the steel /iron products where the gases are venting the timber will appeared to have been burned, the metal will be corroded. The acidic gases caused serious problems when fighting the Lowell fire. In the Lowell shaft the metal corroded to the point where the electrical cable and shaft guides became loose and falling causing a cage to become trapped 600 ft below. The shaft had to have new shaft guides, installed before any further operations could continue this was done by using a very difficult and dangerous method of timbering from the top down using a free cage. Bisbee mine’s had a continual problem of fire gases leaking into the active parts of the mine from the sealed off fire zones. This was caused by the ground cracking from cave in’s and the fires burning into new areas. On several occasions miners were injured from the leaking gases. In 1910 the El Paso Herald reported on the Holbrook 400 level hundreds of mine rat lie dead long the tracks having been asphyxiated from fire gases. Oxygen deficient atmospheres can also be create by the fires With the destruction of mine timber and other ground support systems by the fire, cave-ins and loose ground will become a problem. The danger of being hit by falling material will be great, a hidden danger is an air blast created by the displacement of the air from a cave-in. Theses can force fire gasses to distant parts the mine and other unwanted areas, also the force of the air blast can severely hurt or kill miners. An air blast in a Mexican mine had such force it speeded up a 10 ton locomotive pulling twenty 25 ton mine cars. It derailed the train, stacking three cars on top of the locomotive and killing a total of seven miners underground. Bisbee’s most significant air blast was caused by a regular cave in, not fire induced. In the Holbrook No. 1 mine on July 13, 1907, 75 stope between the 300 and 400 levels collapsed. The miner’s notice the ground was working and had the foreman inspect the stope, the decision was made to abandon it. When the five miners reached the drift below the stope gave way, an air blast was generated it was so strong it knocked everyone down badly bruising them.
Fires can also change the direction of the ventilation in the mine, pumping the fire gases into unidentified parts of the mine. The changes can be drastic like Upcast shafts can be turned into downcast shafts and the reverse. The ventilation changes are in part caused by cave-in’s from the fire.Al Hirales (ex Queen Mine guide) remembers mining into a fire zone in the Campbell. Al and his partner were returning to the face after a blast when they saw a small red glow, they thought someone was smoking a cigarette. When they got to the face they found a small piece of burning timber, then they looked up and saw they had blasted into an old stope and all the timber inside was on fire. The work place was then bratticed off and abandoned.Fire prevention and Emergency planningEarly in the 1900’s mining companies in Bisbee started making a pronounced effort towards safety in the underground mines. Mine fires was one of the main issues, safety rules and emergency plans were developed to prevent fires and injuries/fatalities from fires. The following are some the other changes made for underground fires. Sulfide fires were found to have started primarily in gobbed or partially gobbed stopes, to help prevent fires they stopped filling the stopes with any rock containing pyrite /chalcopyrite. It was also found to be necessary to keep any potential fire area well ventilated to cool the ground to prevent a buildup of heat that could cause a fire. This is very different from coal mines were they try and seal the mined out areas tight to exclude oxygen. In the early years candles were the most common cause of metal mine fires. Copper Queen mining company introduced cast iron sconces into their mines to help prevent fires caused by unattended candle snuffs. The sconces were placed at important areas of the mine like active chutes and main intersections, starting in 1909. Carbide lamps, though they are open flame light like candles caused far fewer fires. Copper Queen mining company pushed the use of carbide lamps in their mines by introducing a special version of the Justrite "Little Giant" style lamp marked "Copper Queen."
Cast iron sconce
With the introduction of mules underground a new fire hazard developed. The manure had to be carefully disposed of because of its ability to ignite, also the storage and disposal of hay.
Signage was implemented with safety rules posted, instructional information and directional signs at all major intersections pointing to the close by shafts and openings to the surface.
Signage on the 400 level of the Czar mine
By 1911 Bisbee mines had helmet crews trained for mine firefighting and rescue. Phelps Dodge would maintain a mine rescue crew for state wide use until around 2006. The Queen tunnel was used as a practice area for the mine rescue teams starting in the 1940’s continuing until the Queen Mine Tour took over. In the tunnel they would practice doing things like installing brattices in low visibility environments to seal off the fire zone, first aid, etc. The tunnel is still blackened near the portal from the burning of oil waste used to create the smoke filled working for the training.
To control ventilation during fires, automated doors were installed on some shafts and in drifts. The doors inside the Southwest mine were installed in 1917.
The position of Fire bug was created, their job was to look for potential fires. They would have runs that that took them to the high risk spots in the mine to look for smoke, heat and the odor.
In the later years a new safety rule prohibiting the smoking of taylor-made (factory made) cigarettes underground allowing only roll your own cigarettes because if unattended the Taylor made’s would stay lighted while the roll your owns would go out. This rule was created from an incident on the 1200 level station of the Cole mine in the mid-1960’s . A miner in a hurry to catch a cage threw away his still lit cigarette, instead of landing on the ground, it went into the shaft causing a small fire. From this point on, all smoking in the underground mines at Bisbee was restricted to hand-made or roll-your-own cigarettes or pipes.
Self-rescuers were brought underground and kept at designated locations with sulfur dioxide filtering respirators. In 1973 the Sunshine mine fire disaster in Kellogg, Idaho killed numerous miners with the release of toxic concentrations carbon monoxide gas from the fire. This caused the Federal Government to mandate that all underground workers be provided with and wear a 30-minute carbon monoxide self-recuer. Bisbee issued theseSelf-rescuers to all underground employees and required them to wear or have them within reaching distance at all times when underground.
W65 self rescuer
Respirator for filtering sulfur dioxide
To help prevent timber fires, for better stability and less maintenance most main production shafts were switched to or design to have steel sets and concrete linings . In the 1980’s with the rehabbing of the Junction adit, a coating of lime was put on the timber to lessen the fire hazard.
Timber coated with lime Junction adit
Rescue chambers for miners to retreat to if escape from the mine was not possible, were installed in the 1980’s. This was done during PD’s attempt to for mine gold and underground maintenance. The rescue chamber were equipped with extra w65 self rescuers, first aid and emergency supplies
Rescue chamber 770 level Junction mine
Major Fire Zones
1902 November 19 Neptune country
1902 Spray mine 40 stope
1904 April 13 Holbrook no.1 in raise from 100 drift
Irish Mag mine 1050 level
1907 November? Stopes on Copper Queen (Gardner) and Calumet & Arizona (Irish Mag) sideline
1907 November 20 Shattuck 800 level station
1908 Holbrook no. 2 mine between 500 and 400 levels
1910 July 27 Holbrook mine 48-29 stope 400 level
1911 January Lowell mine started in 1200-3 stope later encompassed 1000 to 1200 levels
1911 October Holbrook mine 300-55 stope
1912 Holbrook mine “Neptune” area Between 200 & 400 levels
1913 Holbrook Mine between 500 & 600 Levels
1914 Gardner mine 9-1 district 1000 level
1915 December 2 Lowell mine 13-10 stope
1915 December 29 Holbrook mine 3-8-5 raise, between 200 & 300 levels
1916 Whitetail deer shaft fire burned from surface to 150’ level
1919 Shattuck mine 700 level
Between 1915-1920 Briggs mine shaft fire
1920 March 1927 Briggs mine between 1300 and 1400 levels
1923 August 17 Junction mine 1500 level
1924 April 5 Sacramento mine 14-10 country 1400 level
1924 July 30 Lowell mine 12-25 country between 1000 level and 1200 level
1924 August 30 Lowell mine 1400 level
1929 June Sacramento mine 14-10 stope
1932 November 9 Higgins mine shaft fire (vandalism after mine closed)
1948 January 22 Campbell mine started 58 stope 2200 level spread rapidly to 1500 level
1952 Sunrise shaft fire (set ablaze by a surface brush fire after mine closed)
1952 Shattuck mine shaft fire (set ablaze by a surface brush fire after mine closed)
1959 March 7 Copper Queen mine shaft fire (vandalism after mine closed)
1959 Campbell mine
1959 Cole mine
Cole mine 900 level 70 country
1973 1500 level Junction Mine - sulfide fire
1974 Wolverine #2 mine shaft fire (vandalism after mine closed)
1980 January 16 Campbell Shaft electrical fire inside of shaft
Posted instructions on underground fires 400 level Czar mine Photo 1963
Mine Rescue Helmets (McCaa mine rescue apparatus) Donated by the Copper Queen Branch mine rescue team to the Queen Mine Tours
Portable compressed air blower
Ventilation map showing a fire zone
El Paso herald article on recovery of copper from fire country March 28 1911
A 1971 memo regarding the safety hazards of tailor-made cigarettes.
Al Hirales 1994, pers.comm., December
Bisbee Daily Review November 19 1902
Bisbee Daily Review February 14 1904 p.1 ,p5
Bisbee Daily Review April 14 1904 p5
Bisbee Daily Review November 20 1907 p1
Bisbee Daily Review November 24 1907 p6
Bisbee Daily Review July 29 1910 p1
Bisbee Daily Review November 21 1907 p5
Bisbee Daily Review December 8 1911 p5Code of Safe Practice for Emergency Procedures in Underground Mines 1968, Phelps Dodge Corporation pp.23-27
Code of Safe Practice for Emergency Procedures for Fire control and Evacuation in the Cole Mine 1974, Phelps Dodge Corporation pp.1-33
Code of Safe Practice for Emergency Procedures for Fire control and Evacuation in the Dallas shaft 1967, Phelps Dodge Corporation pp.1-33
Compressed Air Magazine May 1918 Vol XXIII No.5 p8766
Details of Practical Mining 1916 Engineering and Mining Journal p250-251
Elements of Mining, George Young 1916 p560
El Paso Herald August 4th 1910 p.7
El Paso Herald January 31 1911 p.7
Henry Hernandez 2010, pers.comm., December
Graeme, R ‘ Bisbee Arizona” Mineralogical Record Sept- Oct 1981 Vol 25 p 274
Metal –Mine Fires Technical Paper 314 Department of the interior Daniel Harrington, Byron O. Pickard,H.M. Wolfin 1923
Notations From Annual Reports years 1909 through 1950 C.E. Mills July 1958
Tombstone Epitaph 13 February 1907 page 1
Richard Graeme IV 2010, pers. comm., 8 February
Richard Graeme III 2010, pers. comm., 2 February
Skillings' Mining Review, v.82, n.10, p.4, 4pp., March 1993
Standardization of Mining Methods Charles A. Mitke 1919 McGraw-Hill book Company pp.66-80
The Copper Queen Practical Mining Course Object Rules and Regulations 1920,
Phelps Dodge Corporation no.19 pp1-19
Procedure for Mine Fires and Shaft Fires 1941, Phelps Dodge Corporation
Procedure of Safe Practice for Haulage 1947, Phelps Dodge Corporation p.15
MSDS sheet Iron pyrite, January 2006,Calumite Company LLC
INFLUENCE OF SEGREGATED MINERAL MATTER I N COAL ON SLAGGING,R. W. Bryers ,Foster Wheeler Development Corporation
Fathi Habashi ,Principles of Extractive Metallurgy Pyrometallurgy vol 3 1986 p181,183
Ventilation of the large Copper Mines of Arizona Bulletin 330 Us department of commerce 1930 pp 62-83